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ECAT Chemistry Chemical Equilibrium Test Online

Maan AliLast Updated: April 19, 2025

Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

Total Questions:	63
Time Allowed:	30 Minutes
Total Marks:	63
How to Attempt Test:	Please choose the right Option in MCQ-type question.
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ECAT Chemistry Chemical Equilibrium Test

Page 1 of 3

Chemistry

1. In a reversible chemical reaction having two reactants in equilibrium, if the concentration of the reactants are doubled then the equilibrium constant will

Becomes one fourth

Remains the same

Be halved

Also be doubled

2. Water and ice are in equilibrium at 0C° and pressure is applied at this stage, then

Water evaporates

More ice is formed

More water is formed

Equilibrium is not disturbed

3. Who studied the effect of temperature on equilibrium?

Lewis

Vant Hoff

Van der Waal

Arrhenius

4. Le-Chatelier’s principle is sometime known as

Law of mobile equilibrium

All of these

Law of mass action

Law of active mass

5. The relationship between Kp and Kc is give by

Kp = Kc (RT)∆n

Kp = Kc (RT)∆

Kc = Kp (RT)∆n

Kp = Kc (RT)-∆n

6. Which statements are correct for a reaction at equilibrium?
(I) The forward and reverse reactions both continue
(II) The rates of the forward and reverse reactions are equal
(III) The concentrations of reactants and products are equal

II and III only

I and III only

I, II and III only

I and II only

7. AgCl dissolved with cone (2 x 10¯²) Ksp will be

4 x 10¯⁴

3.6 x 10¯⁵

3.6 x 10¯⁶

7.2 x 10¯⁶

8. If rate of concentration of reaction is equal to rate of concentration of products in reversible reaction the __________

Reaction goes backward

Reaction goes forward

Reaction stops after some time

Equilibrium will established

9. In reversible reactions, if the forward reaction occur very fast then reactant (s) is (are) __________

At very high temperature

Stable

Solids

Unstable

10. Kc > Products / Reactants favours

Backward reaction

Reaction completed

Forward reaction

Equilibrium

11. Units of Kc is

Moles⁺² dm¯⁶

Moles¯² dm⁺⁶

Moles² dm⁺⁶

Kc may or may not have units

12. When H₂ and I₂ are mixed and equilibrium is attained, then

HI dissociation stops

The reaction stops completely

Amount of HI formed is equal to the amount of H₂ dissociated

None of these

13. Two moles of HI was heated in a sealed tube at 440°C till the equilibrium was reached. HI was found to be 22% decomposed. The equilibrium constant for dissociation is

0.0796

1.99

0.282

0.0199

14. Idea of PH and POH was put forward by

Sorenson

Einstein

Gibbs

Chadwiick

15. A buffer solution can be prepared by mixing

A weak acid and weak base

A weak base and its salt with strong acid

A strong acid and its salt

A strong acid and weak base

16. The rate at which a substance reacts is directly proportional to its active mass and the rate of reaction is directly proportional to the product of the active mass of reacting substances is known as

None of all

Law of mass action

Law of conservation of energy

Le – Chatelier’s principle

17. What is the relationship between kp and kc?

kp = kc (RT)-∆n

kp = kc (RT)∆n

Kc - kp (RT)∆n

kc = kp (P)-∆n

18. At start of reaction, concentration of reactants are on

Lower side

Optimum side

Higher side

Constant

19. For the reaction 2A(g) + B(g) ⇌ 3C(g) + D(g) two moles each of A and B were taken into a flask. The following must always be true when the system attained equilibrium

[B] = [C]

[A] = [B]

[A] > [C]

[A] < [B]

20. Reaction which proceed in both the directions is called

Irreversible

Reversible

Spontaneous

Non spontaneous

21. Which of the following factors will favour the reverse reaction in a chemical equilibrium?

Removal of one of the products regularly

None of these

Increase in concentration of one of the products

Increase in concentration of one of the reactants

22. Synthesis of ammonia by Habor process is an example of ___________

Constant Reaction

Reversible Reaction

Decomposition Reaction

Irreversible Reaction

23. When sparingly soluble salt is in equilibrium with molar concentration of its oppositely charged ion when the product is called

Dissociation constant for an acid

Dissociation constant

Solubility product

Common ion effect

24. A basic Buffer solution can be prepared by mixing

Weak base and its salt with strong acid

Weak acid and its slat with strong base

Strong base and its salt with weak acid

Strong acid and its slat wit weak base

25. When pressure is applied to the equilibrium system Ice ⇌ Water? Which of the following phenomenon will happen?

Water will evaporate

More ice will be formed

Equilibrium will not be formed

More water will be formed

Page 2 of 3

26. In which of the following cases, the reaction goes farthest to completion?

K = 10¯²

K = 10

K = 10³

K = 10⁰

27. The rate of chemical reaction is directly proportional to the active mass of reactant this statement is known as ___________

Law of Equilibrium

Law of reaction

None of these

Law of Mass Action

28. In an exothermic reversible reaction increase in temp shifts the equilibrium to

Product side

Reactant side

Fluctuate

Remains unchanged

29. When ever a week a base is dissolved in water, it gives its conjugate acid similarly a weal acid in water products its conjugate base. The conjugate acid base pair is stated by

Le – Chatelier’s principle

Lowery Bronsted concept

Law of mass action

Common on effect

30. Addition of CH3COOH and CH3COONa gives in water

Both b and c

Acidic buffer solution

Standard solution

Buffer solution

31. For equilibrium 2NO₂(g) ⇌ N₂O₄(g) + 14.6 kcal increase of temperature would

Stop the reaction

Favour the decomposition of N₂O₄

Not alter the equilibrium

Favour the formation of N₂O₄

32. PH of human blood is

7.80

7.00

7.35

7.50

33. Chemical equilibrium is referred to as dynamic because, at equilibrium, the

Equilibrium constant changes

Concentrations of the reactants and products continue to change

Rates of the forward and backward reactions change

Reactants and products keep reacting

34. The reaction 2SO₂ + 2O₂ ⇌ 2SO will be favoured by

Low temperature and high pressure

High temperature and high pressure

High temperature and low pressure

Low temperature and low pressure

35. Which of the following is more acidic?

Bananas

Bread

Apples

Lemons

36. Preparation of buffer solution can be done by mixing

Weak acid and its salt with weak base

Strong acid and its salt with weak base

Strong base and its salt with weak acid

Weak base and its salt with strong acid

37. A chemical reaction A ⇌ B is said to be in equilibrium when

Conversion of A to B is only 50% complete

Only 10% conversion of A to B has taken place

Complete conversion of A to B has taken place

The rate of transformation of A to B is just equal to rate of transformation of B to A in the system.

38. Solubility of any salt can be determined from

Ksp

39. When pressure is applied to the given equilibrium ice water which of the following will happen

Equilibrium will not be disturbed

Water will formed

More water will be formed

More ice will be formed

40. Which set of solutes will form a buffer when dissolved in water to make 1 litter of solution?

0.2 mole of NaCl with 0.2 mole of HNO3

0.4 mole of NH3 with 0.2 mole of HCl

0.4 mole of CH3COOH with 0.4 mole of NaOH

0.0002M HCl

41. The factor which changes equilibrium constant o the reaction A₂(g) + B₂(g) → 2 AB(g) is

Catalyst

Total pressure

Amounts of A₂ and B₂

Temperature

42. Temperature for preparation of SO₃ is

400 – 500 °C

600 °C

200 °C

400 °C

43. Which one of the following is a buffer solution?

Brine

Glue

Solution of CuSO4

Blood

44. An equilibrium constant of 10¯⁴ for a reaction means that the reaction is

One that is unfavourable and will not have very much product at equilibrium

One that will have 50% product and 50% reactant at equilibrium

One that is very favorable and will have mostly product at equilibrium

The equilibrium constant only relates to the speed of a reaction and not to the amount of product formed

45. What can affect the magnitude of equilibrium constant Kp of a reversible gaseous reaction

Temperature

Pressure

Catalyst

None of these

46. In an exothermic reaction, a 10° rise in temperature will

Produce some increase in Kc

Not produce any change in Kc

Decrease the value of equilibrium constant

Double the value of Kc

47. For a reaction H₂ + I₂ ⇌ 2HI at 721 K, the value of equilibrium constant is 50. If 0.5 moles each of H₂ and I₂ is added to the system the value of equilibrium constant will be

0.2

0.02

48. Which pH is considered as basic?

49. When rate of forward reaction is equal to rate of backward reaction, then the equilibrium established is called

Dynamic equilibrium

Chemical equilibrium

None of all

Static equilibrium

50. The product of [0H¯][H⁺] at 25C° is

10¹⁰

10¯¹⁴

10¯²⁰

10¯¹⁰

Page 3 of 3

51. Which of the following aqeous solution will be basic?

NaCl

Fecl₃₋

Na₂SO₄

Na₂CO₃

52. Conjugate base of a very weak acid is

Salt

Strong base

Weak base

Do not ionize

53. The state of equilibrium refers to

State of inertness

Dynamic state

Stationary state

State or rest

54. pH of milk is

6.5

7.5

55. If the value of kc is very low then the forward reaction will occur __________

Randomly

Slowly

Moderately

Fast

56. In a chemical reaction N₂ + 3H₂ ⇌ 2NH₃ at equilibrium point

The reaction has stopped

The same amount of ammonia is formed as is decomposed into N₂ and H₂

Equal masses of N₂ and H₂ are reacting

Equal volumes of N₂ and H₂ are reacting

57. Which of the following gives a basic buffer?

NaOH + NaCl

NaCl + CH₃ COOH

NH₄OH + NH₄Cl

NaOH + CH₃ COONa

58. At certain temperature, 50% of HI is dissociated into H₂ and I₂ the equilibrium constant is

0.25

1.0

0.5

3.0

59. The equilibrium constant in a reversible chemical reaction at a given temperature

Depends on the concentration of one of the products at equilibrium

Is not characteristic of the reaction

Does not depend on the initial concentrations of reactants

Depends on the initial concentration of the reactants

60. If a buffer solution of higher PH than seven is to be made we use

Strong acid and strong base

Weak base and its salt with a strong acid

Weak acid and strong base

Weak acid and its salt with a strong base

61. In reversible reaction the changes in forward and backward reaction occur _________

None

Simultaneously

Both a and b

Individually

62. By the addition of base in water pH will be

Less than 7

More than 7

No effect

Equal to 7

63. The equilibrium will shift towards right by increasing ___________ of reactants

Temperature

Concentration

Impurity

Pressure

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Maan AliLast Updated: April 19, 2025

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ECAT Chemistry Chemical Equilibrium Test Online

Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

ECAT Chemistry Chemical Equilibrium Test

Chemistry

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Chemistry Chemical Equilibrium MCQS Online Test

ECAT Chemistry Chemical Equilibrium Chapter Online Test

ECAT Chemistry Chemical Equilibrium Test

Chemistry

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